Oscillation generator



July-21, 1953 R. H. vARlAN ETAL oscILLATIoN GENEPmoRV original Filedsept. 5o. 1941 2' Sheets-Sheet 1 LJ; (12H2) 4 TTOR/VE Y July 21 1953 R.H. vARlAN ET AL 2,646,512

oscILLATIoN GENERATOR Original Filed Sept. 30, 1941 2 Sheets-Sheet 2 4TTORNEY Patented July 2l 195.3

, "Russell VHfvarian,

Cupertino, William W. Hansen,

Stanford University, and John B. Woodyard, Berkeley, vCalif., assignorsto The Board of Trustees of theyLeland Stanford Junior .University,l"Stanford University, "Calif.,` a corporation-of' California Originalapplication September 30, 194.1, Serial No. 412,918.- Divided and thisapplicationDecemlberlS,T1947, .Serial No. 792,402 y claims. (o1.25o-"361) '1 This invention relates to oscillation generators, moreparticularly 't'o oscillation .generators adapted toproduce ajplura'lityof :high or ultra high frequencies having 'stable frequency differ-ences between them.

Thisappli'cation is a division of application No. 412,918, filedSeptember 30,- 1941, for Object Detecting 'and Locating Systems, nowPatent 2,435,615.

In vmany instances, "it isne'cessary or desirable to .generate aplurality "of frequencies having stable frequency diiferenc'estherebetween. 'For instance, in the previously mentioned parent case,Vthere is Ydiscloseda'multiple channel, con tinu'ous wave,'radar `systemwherein phase differences between'the several channels are utilized to'provide accurate 'ranging information. In order that this information'will havethe required accuracy, it became necessary to generate at leasttwo frequencies having av stable 'frequency difference. y

Accordingly, it is van object of this invention to provide meansforgenerating'two or 'more ultra high frequencies having 'a fixed stablefrequency difference or differences.

Another object is to .provide a plurality of high frequencies 'or ultra'high frequencies having Vfrequency differences Vtherebetween"which may'be accurately controlled :by stable low `'frequency oscillationgenerators.

`Other objects and advantages of the invention will vbe kapparent fromthe following specification and figures, of which:

Figs. .1 andi2-are yschematic views of apparatus for producing two ultrahigh 'frequencies while maintaining a fixed frequency therebetween.

Fig. 3 is a schematic diagram of a circuit for taking =the sum ordifference Vof two three-phase frequencies.

Fig. 4 isa lschematic diagram of Va low frequency three-phaseoscillator.

Fig. 5 isa schematic diagram of a highLfrequency three phase oscillator.

Fig. 6 is 'a schematic diagram` of apparatus for :producing a pluralityof high frequencies separated by stablefrequency differences.

Means for maintaining the desired fixed frequency differences areillustrated in Figs. A1 and 2. In Fig. 11 -an -ultra 'high frequencyoscillator 4, as of the type disclosed in Patent No. 2,242,275, has itsoutput supplied to a modulator 5 to which is also supplied the output ofa high frequency oscillator 6. Thus, if the frequency of the ultra highfrequency oscillator is f1 and that of the high frequency oscillator isf2, the output of the i to select the side'banitl which'is vclosest toTf1, i. e.,

modulator or mixer will then be i-l-fz'and gfijlfz. Actually, thefrequency of the oscillator 4 maybe of the order of 3 1109 cyclesp'ersecond `andthe -frequency of oscillator E may be of theorder'of 10scycles. The output of 'modulator 5 is filtered by filter 'I'Y whichselects 'one side band, ffor 'eX-' ample, )H4-fz and -su'pp'liesthisside band lto an ampliner and modulator "8 to'which isal'so, conL nectedthe output of "a high frequency oscillator 9 whose Afrequency isdesignated asjz-Js where f3 4is o'f "the order of A10,'0'0'0 cycles, forexample, then the output of 'the modulator `8 willfbe fi-i-fa and2f2+f1f3- `A lt'er I'Il is "then 'used fi-l-fs so that .the ouput of theapparatus of `Fig. l is f1 from oscillator 4 and fiel-.T3 from 'lt'erlil.' The frequency difference whichismaintained is derived fromoscillators'l and '9 which are of low frequency .relative to that ofoscillator i4, are f the ordinary radiorange, and can'be maintained withexcellent frequency s'tability. Therefore, the diferencefrequen'oy 73will bevery stable "so that the two frequency Voutputs 'of the apparatusOf Fig. `1 are maintained with 'Sillliliaitl'tiall'y1.111-Y Varyingfrequency difference. f

IIn the vforni -O theappaatus Sli'o'wr'l"1I1`Fi'g- '2, instead of using'the vfilter "I, anfoscillatoi' -II is employed which is locked intostep w'ith the desired side band such, 'for example', as ,f1-Hc.. Ineifect, this Oscillator takes thefplaceof the lilt'e' 7 Fig. I. Alsoanoscillator I-2 isusedin .lieu of filter I 0, otherwisethesestrnctu'res'are similar.

vStill another way of obta'iningtwo ultrahi'gh frequencies having afixed. slight frequency diiference therebetween "isillustrated infliig.v3 .of

vthe drawings. In this ligure, l'high `frequency three vphase current issupplied through leads 'I3 to I5 tothe grids of triodes I6 to I8.` Thegrids -of these tubes are also'supplied with low frequency three phasecurrent over leads 'I9 to 2|. Thus, for example, 'the frequency suppliedover leads I3 to I5 may be of the order of rl07 cycles 3 fraction of asecond, hence the frequency output of leads 22 will have a value, forinstance 107 cycles per second plus 33.3 cycles or 107-33.3, thusobtaining the sum or difference of the two input frequencies dependingupon in which manner the phases are connected. This frequency outputsupplied over leads 22 may now be multiplied by multiplier circuits toan ultra high frequency value such as 3 109 cycles.

The low three-phase frequency supplied through leads I9 to 2| may befurnished by an oscillator of the type shown in Fig. 4 of the drawings.This oscillator 23' comprises three tubes 23 to 25, shown as resistancecoupled and having condensers 26 to 28 and resistances 29 to 3i soproportioned relatively that a 120 phase shift is obtained between eachsuccessive pair of tubes at the desired operating frequency, noting thattube 23 is coupled to tube 24, which in turn is coupled to that is backcoupled to 23. Hence, output leads 32 to 34 will supply three phasecurrent.

A high frequency oscillator 35 for supplying current to leads I3 to I5of Fig. 3 is illustrated in Fig. 5. This oscillator is similar to thatof Fig. 4 except that resonant circuits 35 to 31 are employed in lieu ofresistance coupling, the 120 phase shift between tubes at the desiredfrequency being obtained by the adjustment of these circuits.

Fig. 6 illustrates a means for obtaining three slightly spacedfrequencies. This figure uses the high frequency oscillator 35 of Fig. 5and the low frequency oscillator '23 of Fig. 4 together with themodulator of Fig. 3. In Fig. 6 two low frequency oscillators 23' and 23"of different frequencies are used in conjunction with two modulators 45and 45 to produce two high frequencies, for example, .fA-i-B and fc-l-Bwhich frequencies are then suitably multiplied by multipliers 46 and 45to produce two ultra high frequency outputs of slightly differentfrequency, and the third frequency is supplied by multiplying ,fB fromoscillator 35 in a multiplier 41. lThe frequencies are separated bystable frequency differences, which are accurately determined by lowfrequency oscillators 23' and 23".

Since many changes could be made in the above construction and manyapparently widely different embodiments of this invention could be madewithout kdeparture from the scope thereof, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

1. Apparatus for generating two high frequency voltages having fixedstabilized frequency difference therebetween comprising means forgenerating an ultra high frequency voltage, means for mixing saidfrequency voltage with a lower stabilized frequency, means for selectinga desired side band of the resulting modulation product comprising anoscillator locked in which said side band, means for mixing saidselected side band with another frequency voltage that is slightlydifferent from one of the former frequency voltages, and means connectedto said mixing means for selecting a desired side band of the output ofsaid second mixing means.

2. Means for generating a plurality of ultra high frequencies havingstable frequency differences therebetween comprising, a first stable lowfrequency oscillator, an unstable ultra high frequency oscillator,mixing means connected to said oscillators for mixing low frequency andsaid ultra high frequency, frequency selecting means connected to saidmixing means to select the side bands of said ultra high frequencymodulated by said low frequencies, a second stable low frequencyoscillator, second mixing means connected to said second oscillator andsaid frequency selecting means, and second frequency selecting meansconnected to said second mixing means thereby providing a plurality ofhigh frequencies separated by stable low frequency differences.

3. Apparatus, as defined in claim 2, wherein oscillators are employed assaid selecting means. 4. Apparatus for generating two ultra highfrequencies having a fixed stable frequency difference therebetweencomprising means for generating an ultra high frequency, means formodulating said frequency with a stable lower frequency, means forselecting a desired side band of the modulation produced, means formodulating said side band with another stable low frequency that is butslightly different from one of the former frequencies, and means forselecting a desired side band of said second modu# lation comprising asynchronized oscillator as said side band selecting means.

f5. Means for generating a plurality of ultra high frequency voltageshaving a stable frequency difference therebetween comprising, at leastone stable low frequency oscillator, an ultra high frequency oscillator,mixing means connected to said oscillators for mixing said low frequencyand said ultra high frequency voltages, frequency selecting meansconnected to said mixing means to separate one of the side bands of saidmixed ultra high frequency and low frequency voltages, another stableoscillator, second mixing means arranged to mix said separated side bandand said last oscillator output voltage, and second frequency selectingmeans connected to said second mixing means to separate one of the sidebands of the output of said second mixing means, said latter separatedside band output voltage and said ultra high frequency output voltagehaving a stable frequency difference therebetween.

RUSSELL H. VARIAN. WILLIAM w. HANSEN.l JOHN R. WOODYARD.

References Cited in the file 0f this patent UNITED STATES PATENTS NumberName Date 2,131,558 Granger Sept. 27, 1938 2,231,634 Monk Feb. 11, 19412,234,209 Tollaksen Mar. 11, 1941 2,248,442 Stocker July 8, 19412,265,083 Peterson II Dec. 2,v 1941 2,487,857 Davis Nov. 15, 19492,494,345 Manke Jan. 10, 1950 2,501,591 Bach Mar. 21, 1950 FOREIGNPATENTS Number Country Date 486,448 Great Britain June 2, 1938

